Mixing device



Aug. 28, 1951 o. R. SMITH 2,565,826

MIXING DEVICE 4 Sheets-Sheet 1 Filed April 19, 1948 +13 j if 1 2 2 ,5, F I F n: A /l if a awe/whom 0. R. SMITH MIXING DEVICE Aug. 28, 1951 4. sheetse'sheet 2 Filed April 19, 1948 i wzmmNU gwue/wbcw Oliver Ross Smifh flbtotMR/gb 0. R. SMITH MIXING DEVICE Aug. 28, 1951 4 Sheet-She'et :5

Filed April 19, 1948 l f y 0 #lfi Z W W A 0 f w T 7% 56 0 5 A Z 7 n M W r y w a a w "M alllliilffflllllllglle Oliver Ross Smifh Aug. 28, 1951 o. R. SMITH 2,555,325

MIXING DEVICE Filed April 19, 1948 4 Sheets-Sheet 4 0 Q o o 0 e 'a e Qvwwwkw O/I'ver- R0 55 Smifh Patented Aug. 28, 1951 [TED STATES PATENT OFFICE 'MIXING DEVICE Oliver'Ross Smith, Fort Worth, Tex. --..Applicatin- April 19, 1948, SeriatNo. 21,981

" 3 Claims. '1 This invention relates .to new and. useful improvements inmixing devices.

One object of the invention is. to. provide an improved device for efliciently mixing. paint, asphalt, pitch, tar, road oil or other materials and,

if desired, for simultaneously heating the mav terials.

Another object of the invention isv to provide an improved mixing device havingnovel agitating means in its mixing chamber which is arranged to set up currents-inthe material being mixed so as to circulate the same for obtaining even heat distribution and preventing charring or coking of said material.

An important object ofthe invention is to provide an improved mixing device. having a doublebottomed mixing .chamber to prevent coking of the material thereon, thefplatesof the bottom being secured to each other. at spacedintervals to prevent undue separation of the same and a consequent heat. loss.

.A particular object .of the. invention isto pro- 7 vide an improving mixing. device having its heating means arranged in suchmanner as. to conduct the products of combustion beneathitsmixing chamber .in one direction and along the sides of the chamber in the oppositedirection whereby a maximum heat transfer is had prior .to the discharge of said combustion. products.

Still another object of the invention isto provide an improved mixing device, of the character described, which is of suchconstruction as to be capable of being mounted upon skids or a mobile vehicle so .as to be readily portable.

A still further object of the inventionv is. .to provide. an improved mixing device, of the-character described, having auxiliary. means inlthe lower portion ofthe mixing chamber for heating the material without ookingithereof whenthe agitating means .is. notin operation.

A construction designed to carry outthe. invention. will be hereinafter described together with other features of the invention.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, wherein an example of the invention istshown, and wherein:

Fig. 1 is a perspective view of a mixing. device constructed in accordancewith. the. invention,

Fig. 2 is a front end elevation, partly in section, of the device, the driptroughs beingomitted,

Fig. 3 is a longitudinal, vertical, sectional :view 'of the device,

Fig. 4 is a transverse, vertical, sectional .view, :taken on the .line 4-1 of Fig; .3,

' 2 Eigi 5 is atransverse, vertical, sectional view taken on the line 5-5 of Fig. 3, and

"Fig; 6.isv a detail view of the electrical loadin element.

This application is filed as an improvement upon my copending application, Serial No. 741,- 191, filed April .14, 1947.

In the drawings, the numeral lil designates an agitating or mixing device which includes an enclosed, substantially rectangular body or housi'ng H having upright end walls I2 and side walls IS, a top H and'a bottom I5. Upwardly and outwardly'inclined walls l6 connect the side walls I3 to the bottom l5 which is of less width than the top M (Fig. '2). The housing II is mounted uponspaced, parallel beams or sills H which extend longitudinally beneath its bottom and preferably project beyond the ends thereof. .Due toiits construction, the housing may be placed upon skids or a mobile vehicle (not'shown) so as to be readily portable.

An inner agitating vessel or mixing chamber 18, 'ofless area or size than the housing, is disposed in sa'idhousing in spacedrelation to the walls [2, l3 and 15 and the bottoml5 thereof, whereby afire-box or combustion chamber is is formed between the mixing chamber and said housing bottom as well as said walls I6. The mixing chamber I8 has a forwardly and downwar'dly inclinedbottom 20 (Fig. 3) which is curved or arced transversely (Figs. 4 and 5). Upright walls '2! andside walls 22 extend between the bottomill and the housing top M in spaced, parallelrelation to the housing walls I2 and I3, respectively, whereby flow spaces or passages 23, 24 and 25 are provided therebetween. These spaces serve as vertical and longitudinal'flues and a horizontal partition or baflle 26 separates the rear, vertical flue 24 and the longitudinal flues '25 from the combustion chamber l9. Since the partition '26 terminates at theforward end of. the mixing chamber I8, the front, vertical flue 23 establishes communication between the combustion chamber and. the longitudinal flues which, in turn, discharge into the rear flue 24. An exhaust stack 21, having a hinged or downwardlyfoldable, .upper portion 28, extends fromthe rear flue 24 through'the housing top and rearwall. Sjuitable burners 29 communicate with the rear portion 'of. the combustion chamber and fuel is supplied thereto by a line .30. .Obviously, the products of. combustion or the heat from the burners 29. travels forwardly throughthe combustionchamber beneath the bottom of the. mixing. chamber, upwardly through the flue --23 and is .returnedalong .the side walls 22 throughv the 3 fiues 25 to the flue 24 so as to be exhausted through the stack 21.

In order to prevent coking of the 'bottom 20, the same in preferably formed of a pair of coextensive plates 3| and 32 which are spot welded at spaced intervals. The lower or inner plate 32 is preferably formed of a metal having a higher coefficient of expansion than the upper or inner plate 3! and is subjected directly to the heat of the burners so as to expand or distort relative to said inner plate, thereby providing insulating spaces therebetween and indirect heating of said inner plate. This relative expansion or distortion of the outer plate is limited by the spot welds so as to restrict the space between the plates, whereby undue heat loss is obviated.

Access to the mixing chamber is obtained through a pair of substantially rectangular openings 35 which are formed in the medial portion of the housing top it in transverse alinement. Each opening 34 is surrounded by an upright flange 35 and is closed by a complementary hatch or lid 35. Suitable latches 3? are carried by each hatch 35 for fastening the same to the flange 35.

The mixing chamber bottom 29 has a sump 4! in its forward end portion, toward one side thereof, and a discharge pipe 48 extends from the sump through one of the inclined housing walls IS. A control valve 59 is mounted on the inner end of the pipe 48 and is adapted to be operatedby a vertical stem or rod 55 which projects upwardly through the housing top M. The rod '50 has a handle or lever connected to its upper end. Due to the inclination of the chamber bottom,the material in the chamber drains toward the sump M. An agitator 52 extends longitudinally of the mixing chamber and includes a shaft 53 having its rear end journaled in a bearing 53' mounted on the rear wall 2| ofsaid chamber. The forward end of the shaft 53 is connected by auniversal joint 54 to a drive shaft 55 extending through the forward end walls 2| and I2 of the chamber and housing, respectively,

and journaled in a bearing 56 carried by said wall 2|. A pillow block 5'! supports the front end of the drive shaft 55 which has a drive sprocket 58 mounted thereon externally of the housing. As most clearly shown in Fig. 3, the agitator 52 has a sectional blade or a plurality of blades 59 mounted on the forward portion of its shaft 53 arranged in a continuous left-hand flight or spiral. A similar sectional blade or blades 60, arranged in a continuous right-hand flight or spiral, are carried by the rear portion of the agitator shaft, whereby the material in the chamber is caused to travel toward its center. Since the blades 59 and 55 are arranged in opposite spiral or helical paths, in effect, the same function as separate screw conveyors. For protecting the agitator blades and confining the conveying action of the same so as to cause circulation of the material in definite paths, a perforated or foraminous, semi-cylindrical hood or cover 6| overlies said blades and has depending supports or legs 62 for engaging the bottom 20. Thus, the hood 6! is spaced from the blades and is removable for cleaning purposes. Due to the perforations, there is no interference with the normal heat transfer and limited transverse movement of the material is permitted.

If desired, auxiliary heating means in the form of a steam coil 53 may extend throughout the lower portion of the mixing chamber on either side of the agitator, Suitable supports 64 rest on the chamber bottom for receiving and spacing the coil 63 from said bottom. The steam coil may be used to preheat and melt the material prior to operation of the agitator or may be used as the sole means of heat when high temperatures are not required. To prevent or control overflowing of the mixing chamber, a pair of vent pipes 65 extend through the medial portion of the housing top-I4 between the openings 34 and their flanges 35, forwardly of said top and down the front housing wall 12. Inclined drip troughs 65 are carried by the rear and side walls of the housing to catch any material that overflows or is spilled.

In operation, the material to be mixed and/or reduced to a fluid condition is introduced into the mixing chamber through one of the access openings 34 in the top l4. Since the material is usually in solid form, it is necessary to cut or break the same into small chunks or pieces. As has been explained the material may be heated by the steam coil 53 or by the heat of the combustion chamber l9 and is circulated in the mixing chamber by the agitator 52. Manifestly, due tothe left-hand spiral of the sectional blade 59 and the right-hand spiral of the sectional blade 60, the material in the ends of the mixing cham her is drawn toward the center thereof, and travels longitudinally of said blades within the hoods 6i Upon discharging from the inner ends of the blades, the material passes laterally toward the sides of the chamber and then longitudinally of said chamber toward the ends so as to be drawn into the outer ends of the hoods by said blades. Thus, the material is forced to travel through aplurality of oval paths as shown by the, arrows in Fig. 6. The hoods facilitate this circulation by more sharply defining the paths thereof. Since the. bottom 20 is inclined, material is constantly furnished to the sump 41 without interfering with the circulation of said material. Whenever desired, the mixed material may be discharged through the pipe 58 by swing: ing the lever 5| which opens the valve 49. Due to the provision of the drip troughs 66, the dangel of burning workmen with spilled material is eliminated. Overflowing of the mixing chamber is prevented or controlled by the vent pipes 65. The construction of the mixing device is such that material may be maintained in condition for immediate use for a prolonged period of time and said device may be used indefinitely without cleaning since there is no coking of the material The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within th scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is: I v

1. A mixing device including, a housing, a mixing chamber in the housing having side and end walls, a combustion chamber in said housing beneath the mixing chamber, a rotatable agitator extending horizontally of the mixing chamber,

7 the agitator including a pair of axiallysalined spaced blades having oppositely directed helices for conducting the material being mixed in opposite directions, and a hood enclosing each blade and having open ends spaced from said endwalls, the hoods being spaced from each other, each hood having openings intermediate their-ends to permit limited transverse circulation of the material between the mixing chamber and agitator, whereby the material is drawn into one end of each hood and forced out through the other end thereof to provide definite paths of circulation in said mixing chamber.

2. A mixing device as set forthin claim 1 wherein the helices of the blades are directed toward each other so that the agitator draws the material from the ends of the mixing chamber and forces the same to the center of said chamber.

3. A. mixing device as set forth in claim 1. wherein said rotatable agitator is disposed centrally of the mixing chamber so as to be spaced from the side and end walls of said chamber.

OLIVER ROSS SMITH.

REFERENCES CITED The following references are of record in the file of this patent:

Number 6 UNITED STATES PATENTS Name Date Winding Mar. 25, 1884 Schillinger Feb. 16, 1886 Smith Sept. 13, 1887 Cloud Nov. 15, 1892 Upton Mar. 25, 1902 Avery et a1 Nov. 26, 1907 I-Iussong Nov. 18, 1913 Sartakofi Nov. 12, 1918 Malekow Sept. 12, 1922 Swiers Oct. 31, 1922 Taylor Sept. 11, 1923 Seeley Nov. 5, 1929 Littleford, Jr. May 19, 1936 Baufre Mar. 30, 1937 Schwinger Oct. 1, 1940 Schwinger Dec. 24, 1940 Durham Dec. 12, 1944 

